let arr = [1,2,3,4,123,2]

let arr2 = [
    {id:1, name:'zs'},
    {id:2, name:'as'},
    {id:3, name:'sd'},
    {id:1, name:'zs'},
]

let set = new Set(arr) //特殊的数组，里面的值都是唯一的


// console.log([...set]) //;

let obj ={
    a:1,
    b:2,
    c:3,
    d:4,
}

// let h = 'hello'

// obj[h] =123

// console.log(obj);

let m = new Map()
m.set('a',1)
m.set(2,2)
m.set([2131,12],3)
// console.log(m);

// let reg = new RegExp('asd','q')
// console.log(reg.text('asdfjdsg')) //

let a=1 //等于new number(1) 任何类型都靠new得到 它就是new出来的对象(包装类)
a.b=2  //new number(1).b=2
// delete a.b
// console.log(a.b);//访问对象身上不存在的属性是undefined

console.log(a.toString()); //number构造函数上就有toString 

console.log(0.1+0.2);










